1. Field Of The Invention
The invention relates to a novel process for the preparation of formylimidazoles of the general formula: ##STR1## in which R.sup.1 is hydrogen or an alkyl group, R.sup.2 is hydrogen, an alkyl group, an aryl group or an arylalkyl group, and R.sup.3 is halogen, by catalytic oxidation of hydroxymethylimidazoles of the general formula: ##STR2## in which R.sup.1, R.sup.2 and R.sup.3 are as defined above.
2. Background Art
Formylimidazoles are important intermediates, for example, for the preparation of pharmaceutical active ingredients, such as, diuretics or antihypertensives (International Published Patent Application No. WO-A 92/20651). Several processes for the preparation of formylimidazoles are know to date. Swiss Patent No. 685,496 describes a process in which the catalytic oxidation of hydroxymethylimidazoles to formylimidazoles is carried out in the presence of noble-metal catalysts, such as, platinum-bismuth, platinum black, platinum or palladium on activated carbon, while passing in oxygen. Disadvantages of such process are the long reaction times of several hours and the formation of by-products.